Deaft control device



1941. E. A. FIELD. JR 2,259,130

DRAFT CONTROL DEVICE Filed April 29, 1940 INVENTOR. EDWARD A. FIELD JR A T RNEYS Patented Oct. 14, 1941 2,259,130 DRAFT CONTROL DEVICE Edward A. Field, Jr., Chicago, Ill. Application April 29, 1940, Serial No. 332,236

6 Claims.

This invention relates to improvements in draft control devices.

The main objects of my invention are:

' First, to provide a simplified, highly effective draft control device particularly adapted for use in natural draft heating systems.

Second, to provide a device of the type described which, though simple in its parts, is very sensitive in operation in response to variations in draft to check and increase the same whereby increased economy of operation is made possible. Third, to provide a device of the type described including draft responsive means exposed to the atmosphere on one side and to the vacuum in the smoke discharge duct or breeching on the other and operatively connected to a damper in the duct or breeching for balancing the same to correct excessive chimney draft.

I 'Fourth, to provide a. device of the type described which may be adjusted in a manner to accurately maintain a predetermined draft in a heating unit.

Fifth, to provide a device of the type described wherein the operating parts are completely enclosedv and not subject to being inadvertently thrown out of adjustment.

Further objects relating to details and economice of my invention will appear from the descriptionto follow. The invention is defined in the claims. 'A structure embodying the features of my invention is illustrated in the accompanying drawing, whereini a Fig. l is a top plan view illustrating the draft control device of my invention associated with a natural draft heating unit, for example, a fur- Fig. 2 is a fragmentary view in section on a line corresponding to line 22 of Figs. 3 and 4, further illustrating the construction and arrangement of the parts of my control.

Fig. 3 is a fragmentary view in vertical section on line 3-3 of Fig. 2, further illustrating details of the construction.

Fig. 4 is a view in section on line 44 of Fig. 2.

Referring. to the drawing, the reference numeral I indicates any conventional natural draft heating unit, for example, a stove, furnace, or the like, the duct or smoke flue for the products of combustion of which is indicated by the referencenumeral 2'. This smoke flue has a lateral opening 3 therein in which is disposed an angularly flanged plate or disk 4 constituting an end element for the cylindrical control housing 5.

The plate is suitably secured to the housing and 55 the latter is attached in gas sealing relation to the flue in any desired manner, the housing and flue being in the form of a T when in assembled relation. Housing 5 has a further end plate 6 which coacts with the cylindrical wall of the housing and the end plate 4 in defining a cylindrical control chamber generally designated 1.

Each of the end plates 4, 6 is apertured centrally at 8 to receive a shaft 9, which shaft is rotatably journaled by meansof a pair of rotatable disk-like roller elements [0 on each of the end plates adjacent and beneath the opening. The shaft 9 is reduced in diameter and rides on these rollers at this point to effect a freely rotatable frictionless mounting therefor.

Shaft 9 has securedthereto a vane ll having upper and lower blades [2, l3 respectively of equal area, each approximately equal in length to the length of the control chamber. Shaft 9 likewise extends into the duct or flue 2 and has a damper l4 secured thereto in the latter, the shaft being common to the damper and vane II. The damper and vane are in slightly offset angular relation, as illustrated inFig. 3. The extent of rotative movement of the vane -II is determined by the stops l5 secured to one of the control housing walls.

As illustrated in Figs. 2 and 4, the shaft 9 has a segmental grooved pulley l6 secured thereto exteriorly of the end wall 6, which pulley hasa light chain ll secured thereto with a variable weight I8 on the free end of the, chain, so that the resistance to turning movement of the vane may be adjusted as desired. The space l9 at one end of housing 5, i. e,, to the right of end plate 6 thereof, wherein pulley I 6 is disposed, is enclosed by a flanged. sheet metal cover 20 suitably secured to the housing.

As illustrated in Figs. 2 and 3, the housing end plate 4 has deflectors or 'louvers 2| struck outwardly therefrom to provide openings for communicatingone portion of the housing interior with the vacuum in the duct 2. These louvers at the same time prevent smoke and soot from entering the control housing and fouling the control instrumentalities. By reference to Fig. 3"

in particular, it will be noted that the housing chamber 1 issubdivided into upper and lower portions by the generally horizontal partition members 22 which are spot welded to the cylindrical housing wall and extend radially to points adjacent the center. The uppermost portion of the chamber thus defined by the partition memhe s is as stated communicated with the vacuum in the duct 2 through the openings 23 formed in apertures 26, 21 in the housing end plate 6 the former of which is axially alined with louvers 2|, see Figs. 2 and 4. Thus, the section'of the lowermost housing portion opposite from atmosphere opening is communicated with vacuum through the counterweight space [9 to the right of end plate 6 as viewed in Fig. 2. It follows that the vacuum is effective on both areas on the diametrically opposed sides or portions l2, [3 of the vane, thereby rendering the same double pressure sensitive and quickly responsive, while at the same time balancing the vane dynamically.

In operation, the weight It is selected to maintain a predetermined positioning of damper l4 under normal draft conditions. In Figs. 3 and a, different positions of the damper 14 are illustrated, the closed position in Fig. 3 and the open position in Fig. 4. Once the proper weight has been selected, whenever the difference in pressure between the interior of the smoke duct and the atmospheric pressure in the room in which the unit is installed becomes greater or less than that for which the weight is set, the vane will be turned counterclockwise bythis differential gas pressure or by the counterweight, thus closing or opening the damper l4 and adjusting the vacuum.

in the smoke duct till a balance is reached. Hence, fuel consumption is substantially cut down and combustion efficiency increased. The temperature of the chimney and smoke flue will be greatly reduced; The parts are simple, inexpensive, and readily installed, .but notwithstanding these advantages, the device is very accurate and responsive in its operation.

I have illustrated and described my improvements in an embodiment which is very practical.

I have not attempted to illustrate and describe other embodiments or adaptations as it is believed this disclosure will enable those skilled in the art to embody or adapt my improvements as may be desired.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is: 1 7 Y 1. A draft control for natural draft heating units, comprising a control housing adapted to be attached to the smoke ductof the unit, having a cylindrical body and end plates, a shaft rotat ably journaled in said plates and extending into saidhousing andduct, a damper secured to the shaft in the duct and operative to regulate the draft inthe latter, a vane on the shaft in said housing having diametrically opposed portions on either. side of the shaft, diametrically disposed partitions in the housing dividing the latter into compartments wherein the-respective portions of said vane are disposed, louvers in the end housing ,plate' adjacent theduct communicating one of said 'compartments on one side of the vane portion therein with the pressure in the duct, means defining an enclosed end space adjacent the other .end plate/said last named platehaving diametrically spaced openings therein for also communi-' cating the part of the other compartment on the til opposite side of the other vane portion with the duct pressure through said end space, said housing having further apertures for communicating said compartments with atmospheric pressure on the sides of the vane portions opposite the duct pressure sides thereof, and adjustable counterbalancing means connected to said shaft in said end space for opposing rotation thereof in one direction in response to the difierential between duct and atmospheric pressures, said vane being rotated by duct pressure or by said counterbalance means when -,a difierential between the duct and atmospheric pressures other than a predetermined value arises.

' 2. A draft control for natural draft heating units, comprising a control housing adapted to be attached to the smoke duct of the unit, having end plates, a shaft rotatably journaled in said plates and extending into said housing and duct, a damper secured to the shaft in the duct and operative to regulate the draft in the latter, a vane on the shaft in said housing having diametrically opposed portions on either side of the shaft, diametrically disposed partitions in the housing dividing the latter into compartments wherein the respective portions of said vane are disposed, the end housing plate adjacent the duct having an opening communicating one of said compartments on one side of the vane portion therein with the pressure in the duct, means including a closed chamber in communication with said one of said compartments for also communicating the part of the other compartment onthe opposite side of the other vane portion with the duct pressure, said housing having further apertures for communicating said compartments with atmospheric pressure on the sides of the vane portions opposite the duct pressure sides thereof, and adjustable counterbalancing means disposed in said closed chamber and connected to said shaft for opposing rotation thereof in one direction in response to the differential between duct and atmospheric pressures, said vanebeing rotated by duct pressure or by said counterbalance means when a differential between the duct and atmospheric pressures other than a predetermined value arises.

3. A draft control comprising a control housing adapted to be attached to the smoke duct of a heating unit, said housing having end plates provided with holes and a pair of rotatable elements adjacent and beneath said holes, a shaft rotatably mounted on said elements and extending through said holes into said control housing and duct, a damper on the shaft in the duct operative to regulate the draft in the latter, a vane on the shaft in said control housing having two portions on opposite diametral sides of the shaft, means dividing the housing into compartments wherein the respective portions of said vane are disposed, the housing having a closed chamber associated therewith and openings communicating said chamber and one of said compartments on one side of the vane portion therein with the pressure in the duct, said chamber having an opening for also communicating the part of the other compartmenton the opposite side of the other vane portion with the duct pressure, said housing having apertures for communicating said compartments with atmospheric pressure on the sides of the vane portions opposite the vacuum sides thereof, and adjustable counterbalancing means disposed in said closed chamber and connected to said shaft for opposing rotation thereof in one direction.

4. A draft control comprising a control housing adapted to be attached to the smoke duct of a heating unit, said housing having end plates, a shaft rotatably mounted on said control and extending into said control housing and duct, a damper on the shaft in the duct operative to regulate the draft in the latter, a vane on the shaft in said control housing having two portions extending from the shaft, means dividing the housing into compartments wherein the respective portions of said vane are disposed, the housing having a closed chamber associated therewith and an opening thereto for communicating one of said compartments on one side of the vane portion therein with the pressure in the duct, said chamber having a further opening to the housing for also communicating the part of the other compartment on the opposite side of the other vane portion with the duct pressure, said housing having apertures for communicating said compartments with atmospheric pressure on the sides of the vane portions opposite the vacuum sides thereof, and counterbalancing means connected to said shaft for opposing rotation thereof in one direction.

5. A draft control comprising a control housing adapted to be attached to the smoke duct of a heating unit, a shaft rotatably journaled on the control and extending into said housing and duct, a damper on the shaft in the duct and operative to regulate the draft in the latter, a vane on the shaft in the housing having two radially extending portions, partitions iri the housing dividing the latter into compartments wherein the respective portions of said vane are disposed, said housing having an opening communicating one of said compartments on one side of the vane portion therein with the pressure in the duct and having means including a closed space remote from the duct for also communicating the part of the other compartment on the opposite side of the other vane portion with the duct pressure, said housing having further means for communicating said compartments with atmospheric pressure on the sides of the vane portions opposite the duct pressure sides thereof, and counterbalancing means disposed in said closed space and connected to said shaft for opposing rotation thereof in one direction in response to the differential between duct and atmospheric pressures.

6. A draft control comprising a control housing adapted to be attached to the smoke duct of a'heating unit, a shaft rotatably journaled on the control and extending into said housing and duct, a damper on the shaft in the duct and operative to regulate the draft in the latter, a vane on the shaft in the housing having two radially extending portions, and partitions in the housing dividing the latter into compartments wherein the respective portions of said vane are disposed, said housing having an opening communicating one of said compartments on one side of the vane portion therein withthe pressure in the duct and having means including a closed space remote from the duct for also communi cating the part of the other compartment on the opposite side of the other vane portion with the duct pressure, said housing having further means for communicating said compartments with atmospheric pressure on the sides of the vane portions opposite the duct pressure sides thereof.

EDWARD A. FIELD, JR. 

